Protection for electric meters.



G. R. HADLEY. PROTEUTION FOR ELECTRIC METERS;

APPLICATION FILED NOV. 8, 1905v Patented May 4, 1909 25 cal section on the line 2,

GUY HADLEY, Ol "l\lILWAUKEE, WlSOQNbIN.

- PROTECTION FOR ELECTRIC METERS.

' Specification of Letters Patent. 1

Application filed November 8,

To all whom it may concern:

Be it known that I, GUY R. RAminY, a citizcn of the United States, residing at Milwaukee, in the county of Milwaukee and State of parts as hereinafter particularly described and pointed out in the claims.

In the accompany inc; drawing! designate the some parts in both figures.

Figui e 1 is a front elevation of a three-wire meter and. its connections, provided with a protective inclosure embodying the invention, the front or cover of the protective box or case being removed; and Fig. 2 a verti- 2, Fig. 1 of the box cover but omitting. the

ike letters or case, including the wiring. I

In the commercial incasurrmient of elci,

tricity with meters as now constructed, it

found that errors frcqiicnlly occur due to ccrtain causes external to the meter itself;

These causes, whether purcl .accidental or the result of a prmucditated plan to d:

may be mechanical, clertricai or n,- nature, as indicated in the followi' Mcrhaniml in sioned.

fa) B drilling. a hole in the cover or base of the meter and inserting a- ;wire far enough 40 to touch and stop or retard Themoving ole ment of the meter. i l

(7)) B5. inserting a wire between the cover and base or tl'irough the regular wire hole alongside of the conductor therein in such a way to touch and stop or retard thenrovinc; part of the meter.

(0) By removing or loosening the supporting screws or other fasteningsand tipping the meter so as to stop or retard it.

(d) B cracking the jewel, which may be accomplished by a sharp blow on the base, thus causing the meter to run slow on large list: icrl'cr nr-imay be occa- Patented May 4, 1909. 1905. Serial No. 286,345.

loads and to entirely fail to register small ones. i

(6) By allowing water or acids to fall on meter, the usual felt packing strip permitting its entrance into the meter with resultingdamage by electrolysis.

2. Electrical interference may be occasioned, q

(a) By tapping the service wires on one side of the meter and connecting them with the wires on the other side, a concealed switch in this shunt making it possible to defraud whenever desired.

(Zr) By forcibly pulling; certain of the wires out of the binding posts meter, and then inserting such wires again when the ins ector is expected.

(c) B breaking the neutral tap. (Reneatedbeudins may cause a copper wire to break inside of its insulating co'vering'. "T he meter will then register only when the ends happen to touch each other.)

(a!) By removing the service fuse in an outside wire of a three-wire meter whose )0- tr-ntial circuit connertml from such outside wire to the neutral wire, thus stopping the meter, it being; then possible to use half the full load throng-h the other fuse withoutrer 'stral'ion.

(c) in thrcase cited in paragraph d, by running" a jumper from the dead wire to the other outside wire, thus permitting the whole load to be used whil the meter regislcrs the difference of load between the two sides of thcsystcm instead of the sum.

(f) And in case the service fuse be concralcd or inaccessible, the fuse on the poten tnzl side may be blown by;

a ground or slrorla-ircuit on that side with the-same result as stated in para, raph (l.

interfered with magthus stopping thenu'posely making The invention consists broadly in moles-- ing an electric meter and its connections in aprotective case and conduit whereby they are made inaccessible, and interruption of and interference with the normal and proper operation of the meter, by the above enumerated causes are prevented.

Re'ferringto the drawing, a designates a three-wire electric meter of a well known type containing field coils, an armature or rotating element, and a drag or brake magnet, which are not shown and need not be d e-1 scribed since their nature and operation are well understood by those familiar with the art to which this invention pertains.

Z; designates the service or supply wires leading to service or supply cut-outs c, which are provided as usual With inclosed fuses of a rating at least double the safe carrying From these cut-outs capacity of the meter. the service or en ply wires lead, as shown in Fig. 1, to the lie d coils of themetcr. thence back to cut-outs d which are also provided with inclosed fuses but of a rating only slightly in excess of the rated capacity of the meter. From the cut-outs (Z lead the outside wires c of the utilization or working circuit. The reason for the two sets of fuses above mentioned is that any over-load or short-circuit on the utilization orworking circuit m'll blow or'melt only the smaller fuses,.leaving potential on themeter arma- I ture, and only in case of a breakdown of the insulation of the meter itself are the larger fuses required to prevent total destruction of or serious injury to the meter which would occur if no fuses were provided between the supply mains and the meter.

A tapf to supply potential to the'armatnre of the meter is taken off from the neutral wire which is designated 1) e, and passes directly from the service or supply to the utilization or working circuit Without the inter position of a fuse or cut-out. The meter and connections thus briefly described are such as are commonly used in a three-wire direct current system, and of themselves do not constitute the present invention.

The meter a, with the cut-outs c and (Z and 2 their connections with each other and with the wires of the service and utilization circuits, arc incloscd in and protected by a metallic box ormasc {1 against premeditated or accidental meddling or ii'lterference This box, which is provided with a rcmovf able cover it, as shown in Fig. 2, may be con screws 1', the heads of which are countersunk 1n the cover. as shown in Fig. 2, and are suitable material.

A glazed opemngy is provided-1n the cover protective box or case.

,The service or supply Wires 5 5 leading to themeter, and the wires e e of the utilization or working circuit leading from the meter, are inclosed in and protected by iron ipes or tubular conduits k which are secure at the ends in the base or body of the protective box or case 9 by lock nuts I or other fastenings which are inaccessible from the outside when the box or case is closed, and which prel vent detachment and removal of the pipes from the box unless the box is o ened. These pipes or conduits eXtenda su cient sealed with wax, plaster of paris, or other any suitable means, such fohexarnrxla'ithiifi for reading the meter Without opening the 4 distance from the meter to prevent tapering,

or interference therewith or unauthorized connections being made in any of the ways hereinbcfore mentioned.

In new buildings the base or body of the vbox g is preferably let into and permanently secured'in a wall bythe workmen who install I the piping or wire conduits which are secured l in the box or case as above explained. When theme-ter is installedin an old building the f box may be fastened to a wall or other'support by screws passing through the back, or iby other fastenings which are inaccessible from the outside when the boX is closed.

1 Various changes in minor details of construction and in the arranrement of parts may be made without departing from the principle and intended scope of the invention.

I claim: I p

1. The combination with an electric meter and wires leading thereto and therefrom on the service and the utilization sides respectively, of fuses. disposed on the service and the utilization sides of the meter, the fuse in circuit after the meter being of such a cal pacity as to be blown before the fuse on the {service side, and a'metallic case inclosing said fuses and preventing unauthorized access thereto, substantially as described. i 2. The combination with an electric meter and wires leading thereto and therefrom on the service and the utilization sides respecj tively, of fuses disposed on the service and l the utilization sides .of the meter, the fuse in circuit after the meter being of such capacity as to be blown before the fuse onthe service I sidc,*a metallic case inc-losing said meter and fuses and protecting the same against unauthorized interference, substantially as de scribed.

3. "l ho combination with an electric meter and Wires loading thereto and therefrom on the service and the utilization sides respectively, of fuses disposed on the service and the utilization sides of the meter, the fuse in outside when the case is closed, substantially circuit after the meter being of such capacity as described. i0 as to lie blown before the fuse 0n the service a In Witness whereof 1 hereto affix my signas l 9 a, metallic case inclosing fuses, a ture in presence 01" fi m) Witnesses.

LmUlLl metallic conduit inclosing the wire GUY IR. HADLEY calling to the fuse on the service side of the Witnesses 1 CHAS. L. G0 BERNARD O Relies? .ler and IL fastening securing said conduit \Ylllllll the case and inaccessible from the i l l i l i i 

